The present invention relates to a mold, particularly a mold of steel for manufacturing objects of concrete in accordance with a centrifugal casting method.
Casting molds of the type under consideration have been known. One of such casting molds, disclosed in German Offenlegungsschrift No. 1,907,226, is formed of two mold halves provided with opposing flanges at which the mold halves are open or closed. An outwardly projecting wedge is secured on the upper side of the longitudinal flange of the upper mold half whereas the longitudinal flange, projecting outwardly from the lower mold half over the flange of the upper mold half, is extended outwardly and angled upwardly so that it receives the upper flange along the longitudinal edge thereof, whereby a number of counter wedge abutments are formed on the upper side of the lower angled flange which overlap the wedge so that the mold halves can be clamped to each other upon a mutual displacement of the mold halves in the direction of elongation. In this known clamping device, difficulties, however, occur during the clamping of two mold halves to each other because the upwardly bent lower flange can be slightly contaminated during the filling of the mold with a filling material, and the cleaning of the mold is then extremely difficult. Furthermore, the arrangement of the wedge, as well as the abutments for this wedge, outside the plane of separation between two flanges of the mold causes a non-uniform loading of mold halves during the clamping, and the abutments on the lower flange are very difficult to adjust to provide a uniform clamping at all abutments for the wedge in the closed mold.
German Auslegeschrift No. 1,065,769 discloses a clamping device for securing two portions of a cylindrical centrifugal casting mold for producing tubes of cement to each other. Two opposing longitudinal flanges of the two mold halves are clamped to each other by a hinged clamping lever displaceable in the direction of flanges and two oblique surfaces, of which one oblique surface is provided on the clamping lever engaged with one flange and the other oblique surface is provided on the flange of the opposite mold half, whereby the clamping of two flanges to each other is obtained by a hammer blow exerted on the flanges in the longitudinal direction thereof relative to the clamping lever. The clamping lever slides with its wedge shoe carrying one oblique surface along the axis parallel to the longitudinal flanges, and a locking of the mold halves is obtained by the hammer blow exerted in the opposite direction. In this other construction of the clamping device the arrangement of two cooperating oblique surfaces outside the plane of separation between two flanges causes again a non-uniform clamping of the mold, which affects a further centrifugal casting process.